Generally, when a collision occurs while a vehicle is in motion, the external force causes the upper body of a driver to lunge forward. This causes the driver's chest or face to contact the steering wheel, resulting in injury to the driver. Injury may also occur to the driver's legs, particularly the knees or shinbones, when contact is made between the drivers lower extremities and the dash panel or steering column.
Typically a shroud is installed that wraps around the steering column to conceal the steering column and absorb impact to the driver's knees to a certain degree. The shroud is conventionally made of a thin plastic material that simply wraps around the steering column providing only a nominal impact absorbing effect. Furthermore, the shroud often breaks up upon impact of the driver's knees at the time of a collision. Additionally, the steering column is generally made of steel and shaped in the form of a sharp-edged rectangle.
A polypropylene shock absorbing padding has been inserted on the internal side of the shroud in an attempt to absorb a greater impact. However, the pad is ineffective in absorbing most impacts. This is particularly the case when an electromotive tilting steering column is used in the vehicle because the space available for installing the pad is limited and thus, the pad becomes to thin.
Furthermore, in the event of an offset frontal collision, the impact is likely to cause the vehicular body to spin resulting in the legs of the driver being thrown laterally. This lateral movement causes the driver's legs to bump against the steering column. Therefore, an adequate knee protection device must also guard against contact with the side of the steering column.